The goal of the proposed research is to provide to the radio-therapy community the design of a medically practival generator of negative pi-meson beams of sufficient intensity and quality for therapeutic application. The research program for developing the various components of the pion generator will be conducted with emphasis upon the constraints inherent in providing medical equipment which is to be extensively useful: compactness, reasonable construction and operating cost, reliability, and simplicity of operation. The end point of these studies will be a medical pion generator design compatible with typical hospital facilities with firmly established operating parameters and cost. The results of this program will also be applied to deuteron or proton accelerators suitable for providing protons or neutrons for therapeutic purposes. The proposed work is predicated on the successful evaluation of several new advances in accelerator technology demonstrated in the PIGMI prototype accelerator at LASL under the initial grant. The prototype includes injector, rf, low energy accelerator, control, and instrumentation subsystems. Continuing work will concentrate on use of the prototype to define a final design, testing a powered prototype of the high energy accelerator, developing plans for a hospital compatible neutron generator utilizing the PIGMI technology, and investigation of pion-channel designs.